1026 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[June 21, 1871. 
ported in its natural state, should not be stored without 
a licence.” ... “I have, therefore, come to the conclu¬ 
sion ” ... “ that the petroleum, not being a manufac¬ 
tured petroleum but petroleum proper, may not be kept 
and stored without a licence.” 
The new reading of the Acts as embodied in this 
judgment, therefore, amounts to this, that “ petro¬ 
leum ” (legally spealdng) has a double meaning; it 
means:— 
1. Any product of petroleum or other substance men¬ 
tioned in the Act of 1868, provided it give off inflam¬ 
mable vapour below 100° F. 
2. Petroleum proper (as distinguished from the pro¬ 
ducts of petroleum), or, in other words, crude petroleum, 
unconditionally. 
This new reading, though doubtless at variance with 
the intention of the Legislature, is, as will be seen, of 
no practical importance, if it be understood, as crude 
petroleum is not now imported; it is however a hard¬ 
ship that dealers should be subjected to the unjusti¬ 
fiable annoyance, arising from those in authority 
being unacquainted with the real meaning of the 
judgment. 
It should be distinctly comprehended that the oil 
imported from America, known in the wholesale 
trade as “ refined petroleum,” and sold in the shops 
under {the names “petroleum,” “rock oil,” “crystal 
oil,” etc., is, not only scientifically, but also in the 
eye of the law, “ a product of petroleum,” and that, 
as such, no licence is needed for storing it, provided 
it does not give off inflammable vapour below 100° 
F. when tested in accordance with the Act. 
Note. —Since the above was forwarded to the 
Editor, a Petroleum Bill, now before the House of 
Lords, has been printed. Tins Bill contains a new 
interpretation clause, which is a great improvement 
on those of the existing Acts; and although the term 
“include,” which has caused so much trouble, again 
makes its appearance, there can be no doubt that, 
should the Bill become law (in which case the Acts 
of 1862 and 1868 would be repealed), much of the 
ambiguity which at present attaches to the w r ord 
“petroleum” would be removed.—B. B. 
“Baltic” B.C., June 19 th. 
(Oraptcrs hr jltuiitnts. 
CHEMICAL NOTES TO THE PHARMACOPOEIA. 
BY WILLIAM A. TILDEN, D.SC. LOND. 
DEMONSTRATOR OF PRACTICAL CHEMISTRY TO THE 
PHARMACEUTICAL SOCIETY. 
Hydrargyri Subchloridum.— Mercuric sulphate 
is first triturated with a quantity of metallic mercury 
equal to that which it already contains, the combina¬ 
tion being assisted b} r moistening with a few drops 
of water. A grey powder is thus obtained which is 
practically mercuiws sulphate. 
Hg S 0 4 -f Hg = Hg 2 S 0 4 . 
From this equation HgS0 4 , or 296 parts of the 
sulphate, require Hg or 200 parts of the metal, form¬ 
ing 496 parts of the mercurous sulphate. 
Chloride of sodium is then added and the mixture 
sublimed with the aid of a pretty strong heat. 
Hg 2 S0 4 + 2 Na Cl = 2 Hg Cl -f Na 2 S 0 4 . 
If the sublimation is conducted in a small flask or 
pot, so that the vapour condenses upon a warm sur¬ 
face and but slowly, crystalline masses are obtained, 
a form which would be unsuitable for administration 
in medicine. The vapour is therefore driven from 
the subliming pot into a pretty large brick chamber, 
in which, in consequence of the sudden cooling 
effected, the calomel condenses in the form of a fine 
dust. This is washed with boiling water, to remove 
from it the traces of corrosive sublimate that are 
invariably produced. 
Calomel, in the pulverulent state, as produced by 
sublimation, is not a white powder, but has a yellowish 
tint, which is increased by trituration in a mortar. 
[§ Digested with solution of potash, it becomes 
black; and the clear solution, acidulated with nitric 
acid, gives a copious white precipitate with nitrate of 
silver.] The black compound is of course mercurous 
oxide, chloride of potassium being left in solution. 
[§ Contact with hydrocyanic acid also darkens its 
colour.] The result, however, is not a definite mer¬ 
curous cyanide, but a mixture of metallic mercury, 
calomel and a cyanide, or probably a clilorocyanide. 
[Warm ether, which has been shaken with it in a 
bottle, leaves, on evaporation, no residue.] This 
shows the absence of corrosive sublimate. 
Calomel may be prepared according to other me¬ 
thods ; one wliicli was at one time employed con¬ 
sists in precipitating a solution of mercurous nitrate 
with common salt. 
In undergoing volatilization, there can be no 
doubt that calomel undergoes decomposition into 
free mercury and mercuric chloride, recombination 
ensuing when it again condenses. In consequence 
of tills, the specific gravity of the vapour connot, in 
tliis case, be taken as any evidence of molecular 
weight. 
Hydrargyri Sulphas. —Mercury is boiled with 
strong sulphuric acid, the heat being continued until 
the metal lias disappeared and a dry, white, crystal¬ 
line powder remains:— 
Hg + Ho 0 2 S 0 2 -f Ho S 0 4 
Sulphuric acid. 
= HgS0 4 + H 2 0 + IDO + S0 2 . 
Mercuric Water. Sulphurous 
sulphate. acid gas. 
Mercuric sulphate is decomposed by water with 
formation of “ turpetli mineral,” a mercuric oxysul- 
pliate:— 
3 Hg S 0 4 + 2 H 2 O = Hg 3 S 0 4 0 2 + 2 H 2 S 0 4 . 
Hydrargyrum. —This important metal is obtained 
almost exclusively from the native sulphide, Hg S or 
cinnabar, by one . of two processes. Either the 
mineral is roasted in a current of air, which oxi¬ 
dizes the sulphur into the permanently gaseous S 0 2 , 
the mercury being simultaneously carried in the 
state of vapour through a series of earthen pipes, 
where it condenses to the liquid state and runs into 
a reservoir; or the powdered mineral is distilled 
with lime, when a mixture of sulphide and sulphate 
of calcium remains behind with the excess of lime 
and the gangue, and metallic mercury distils over. 
The impurities contained in the mercury of com¬ 
merce are principally traces of lead, zinc, tin and 
bismuth. Mercury so contaminated does not form 
bright spheroidal globules, but each one leaves a 
trail behind it. These impurities are best removed 
by redistillation, but the mercury may also be 
rendered sufficiently pure for ordinary purposes by 
